1. Field of the Invention
The present invention relates to a device and method of filtering the exhaust from a commercial kitchen or other high particulate air exhaust. In particular, the present invention relates to a filtering device which is positioned in the exiting air flow of the exhaust of a commercial exhaust such that it filters a substantial portion of the particulate matter wherein there is no substantial obstruction of the flow from the exhaust.
2. Description of Related Art
Commercial kitchens that cook with grease, such as restaurants, use rooftop mounted exhaust systems during the cooking process. Air born grease generated during the cooking process is discharged up through the venting system. This venting system usually forces all the air through a washable metal filter, which particulate grease matter can condense on, before the air is discharged by the exhaust fan out the final exhaust port on the roof. The air filters used in commercial kitchens are metal, low back pressure, high volume air flow type filters because fine filters, as used in air conditioning systems, back-up air flow and prevent efficient exhaust of air. Filtration is not efficient with these types of filters when the air is saturated with grease or other particulate matter. The exhaust air in most commercial kitchens is so grease laden that a large percentage of the grease by-passes the filters and ends up ejected out the final exhaust roof port and distributed on the roof and any other area surrounding the final air exhaust port. This deposited grease builds up quickly causing a need for frequent roof cleanings and replacement of roofing materials, before their otherwise useful life ends. Where the grease is ejected far enough from the exhaust port it can damage near-by devices, such as HVAC and refrigeration units, on the roof and even be ejected off the roof damaging landscaping and anything unfortunate enough to be on the ground close to the building such as cars.
While currently there are many methods that attempt to deal with this issue, there is currently no solution that adequately solves the problem of air born grease or other particulate material which is discharged from a commercial kitchen exhaust or other rooftop exhaust. One method of attempting to fix this problem is to surround the area directly around the exhaust port with a material that is removable and replaceable. This approach wastes large areas of the roof preventing other uses of the roof and doesn't prevent wind or other interfering circumstances from depositing grease beyond where the material is placed. In addition, since the area of distribution of grease is generally large, such material is very costly to use and hold in place. Other methods usually involve creating convoluted air flow toward the exhaust outlet port in hopes of grease condensing on the exhaust path walls and doesn't prevent all grease from being thrown onto the surrounding roof area. This also requires frequent cleaning and adds to the problem of potential exhaust grease fires.